![]() ![]() An incredible amount of data collected over the last century has strengthened the case for the Big Bang, and also shown it to be even more bizarrely strange than first thought. Of course, we now call this moment the Big Bang. Taken together with Hubble's law, the implicaiton is that everything-matter, energy, space, and even time-all started as a singularity-a point of infinite density, without any size at all. The galaxies are moving farther and farther apart like beads strung along a stretching band of elastic. The most exciting implication of the Hubble Law is that, if everything is moving away from us now, everything must have been closer and closer if you go further back in time. If we rewind the Universe's clock far enough (about 13.7 billion years) then we find that everything in the Universe must have been at the same spot at the same time.Įven more strangely, research since Hubble's time has shown that all these galaxies are not moving through space at great speeds, rather space itself is expanding. Hubble found that the further away a galaxy was from us, the faster it was moving away from us. This is called Hubble's Law and, when plotted, the slope of the graph is called the Hubble Constant. Until astronomers developed infrared telescopes, the most distant universe was hidden from them. One consequence of the Hubble Law is that if you want to look at the most distant galaxies in the universe, their light will be shifted entirely into the infrared part of the spectrum! When he combined that information with their distances, the result changed the way we view the Universe. This shifted their light to longer wavelengths, more towards the red side of the spectrum. Indeed he found that not only were galaxies all moving, almost all of them were moving away from us. Light waves, like sound waves, are subject to the doppler effect, and Hubble was able to use this phenomenon to measure the speeds of galaxies. If it moves towards us we hear a higher pitch (or frequency), while the pitch shifts lower if it is moving away from us. The shift is stronger the faster the vehicle is moving. You may have heard the pitch of the siren on an energency vehicle changing as it passes you on the street. It is caused by the doppler effect, which we commonly encounter here on Earth with sound waves. Redshift is a term that refers to a shift in the wavelength of light from an object resulting from its motion towards or away from us. Humason, to measure the galaxies' redshifts to determine how quickly they were moving. Having measured the distances to the galaxies, Hubble worked with fellow astronomer, Milton L. His measurements, which built on the research of Henrietta Swan Leavitt, showed that these "nebulae" were far too distant to be part of our own galaxy, and were, in fact galaxies in their own right. Hubble measured the distances to a number of galaxies, which had been long believed to be "nebulae" within our own Milky Way Galaxy. Hubble made his historic observations of galaxies using the 100" Hooker telescope on Mt Wilson, near Los Angeles, California ![]()
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